Geophysical Mapping of Freshwater-Saltwater Interfaces: Examples from the Coastal Plain Aquifer System of
North Carolina
Lewis LandNew Mexico Bureau of Geology and Mineral
Resources
Central Coastal Plain Capacity Use Area (CCPCUA)
• Encompasses 15 counties in eastern North Carolina, within which ground water use will be regulated to protect long-term productivity of aquifers beneath the coastal plain.
• 100,000 GPD threshold for permitting ground water withdrawals from Cretaceous and Tertiary aquifers.
Summary
• A TDEM sounding used alone does not provide the same degree of vertical resolution as a borehole record.
• However, a much higher effective level of precision can be attained when TDEM soundings are integrated with existing borehole data, effectively increasing the density of subsurface information by several hundred percent.
Summary
• Electromagnetic soundings provide an efficient, inexpensive, and semi-quantitative method for evaluating ground water resources in coastal aquifers, on both local and regional scales.
